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Drobo 5D Read/Write Performance

Last updated 2013-02-01 - Send Feedback
Related: Storage, Backup, storage, Thunderbolt

B&H Photo supplied the Data Robotics Drobo 5D for testing, along with five Hitachi 4TB hard drives.

Testing was on the fast 2.7 GHz MacBook Pro with Retina display via Thunderbolt.

Sequential read/write performance

The Drobo 5D when configured with five 4TB drives is a huge volume, and it simply takes longer than I wanted to run the test (at least 24 hours).

So instead, it was handed an easy test: a 1TB partition out of the ~15TB of capacity. This should allow the Drobo 5D to show its very best performance. Actual performance is likely to be slower as capacity fills up and the slower areas of the drives are used.

A small portion of the capacity was tested 1TB (TB=1000^4)

Fill-volume performance on 1TB partition

For perspective on the figures that follow, Thunderbolt is capable of up to 1000MB/sec, with realistic real-world figures in the 650 MB/sec range. A single fast hard drive is capable of nearly 180MB/sec or even a little more.

This test was run on a 1TB partition, presumably the fastest part of the ~15TB of available storage. It was the first partition created by Disk Utility (2 partitions created, with regular hard drives the first partition is always the fast one).

Write performance is somewhat better than a single fast hard drive. From the sound of it, the Drobo 5D does a significant amount of head seeking in order to write parity information.

The dropoff in write performance as the test progresses is not encouraging, nor are the inconsistent up/down spikes. This would not be a good choice for 1080P video capture (dropped frames).

Read performance is more than adequate for many tasks and should prove quite satisfactory for most users.

It appears that the Drobo would make a poor choice for a scratch drive or similar (slow writes), but that as part of workflow in which reads dominate it would perform at a very satisfactory level. Generally speaking, reads happen many times, and writes happen once (for image files, video, etc).

Sequential read and write speed (DiskTester)
Drobo 5D via Thunderbolt on 2.7 GHz MacBook Pro Retina

Run sequential

MPG testing always uses the command line version of DiskTester as shown below.

  • Write performance is somewhat faster than a single fast hard drive (remember, the Drobo 5D is using five fast 4TB drives).
  • Read performance is less than one might hope for. Still, it is more than adequate for many purposes, and faster than a SATA II 3 Gbps can perform.


llcR:DIGLLOYD lloyd$ disktester run-sequential -i 10 -t 16G d5d
DiskTester 2.2 64-bit, diglloydTools 2.2.0, 2012-12-15 18:05
Copyright 2006-2012 DIGLLOYD INC. All Rights Reserved
Use of this software requires a license. See
OS X 10.8.2, 8 CPU cores, 16384MB memory
Thursday, January 31, 2013 19:29:20  Pacific Standard Time
disktester run-sequential -i 10 -t 16G d5d
Allocating maximum size contiguous file on "d5d" (16.0TB)...16.0TB (99.9% of volume size)
TEMP FILE: /Volumes/d5d/disktester-test/DiskTester-Temporary-Test-File
Using test size of 16GB, 4MB at a time at start (0%), within a 16.0TB test file.
Iteration 1: writing...203MB/sec, reading...292MB/sec
Iteration 2: writing...213MB/sec, reading...374MB/sec
Iteration 3: writing...227MB/sec, reading...373MB/sec
Iteration 4: writing...233MB/sec, reading...364MB/sec
Iteration 5: writing...229MB/sec, reading...368MB/sec
Iteration 6: writing...232MB/sec, reading...361MB/sec
Iteration 7: writing...234MB/sec, reading...362MB/sec
Iteration 8: writing...233MB/sec, reading...367MB/sec
Iteration 9: writing...233MB/sec, reading...370MB/sec
Iteration 10: writing...232MB/sec, reading...366MB/sec
Thursday, January 31, 2013 19:29:20  Pacific Standard Time, volume "d5d" (16.0TB)  
----------------- Averages for "d5d" (16GB/4MB, 10 iterations) -----------------
Iteration 	Write MB/sec	Read MB/sec
1    	     203    	    292    
2    	     213    	    374    
3    	     227    	    373    
4    	     233    	    364    
5    	     229    	    368    
6    	     232    	    361    
7    	     234    	    362    
8    	     233    	    367    
9    	     233    	    370    
10    	     232    	    366    
Slowest  	     203    	    292    
Fastest  	     234    	    374    
 Average  	     227    	    360    
Median  	     232    	    367    
Range   	    31.3    	    81.3   
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